Embodiments of the present inventive concepts relate to an interface circuit, and more particularly, to an output driver using an n-type metal-oxide semiconductor (NMOS) transistor as a pull-up driver, devices having the same, and/or ground termination.
A conventional output driver is connected in series between a power line and a ground line and includes a PMOS transistor used as a pull-up driver and an NMOS transistor used as a pull-down driver.
As carrier mobility, e.g., hole mobility, of the p-type metal-oxide semiconductor (PMOS) transistor is less than carrier mobility, e.g., electron mobility, of the NMOS transistor, a size of the PMOS transistor may be designed 2.5 times bigger than a size of the NMOS transistor.
A size of a first pre-driver driving the PMOS transistor is designed bigger than a size of a second pre-driver driving the NMOS transistor. Accordingly, an amount of current flowing in the first pre-driver is more than an amount of current flowing in the second pre-driver.
Moreover, as the NMOS transistor operates in a linear region when a power voltage is used as a termination of a channel transmitting an output signal from an output driver, a current flowing in the NMOS transistor should be increased for desired data signaling.